Superimposed displays

ABSTRACT

Various embodiments of methods and systems for constructing and utilizing displays constructed from superimposed display subunits are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to, claims the earliest availableeffective filing date(s) from (e.g., claims earliest available prioritydates for other than provisional patent applications; claims benefitsunder 35 USC §119(e) for provisional patent applications), andincorporates by reference in its entirety all subject matter of thefollowing listed application(s); the present application also claims theearliest available effective filing date(s) from, and also incorporatesby reference in its entirety all subject matter of any and all parent,grandparent, great-grandparent, etc. applications of the followinglisted application(s):

-   -   1. United States patent application entitled ELEMENTS FOR        SELF-ASSEMBLING DISPLAYS, naming W. Daniel Hillis, Nathan P.        Myhrvold, Clarence T. Tegreene, Lowell L. Wood, Jr., and        Victoria Y. H. Wood as inventors, filed Mar. 11, 2005, Ser. No.        11/078,207.    -   2. United States patent application entitled SELF ASSEMBLY OF        ELEMENTS FOR DISPLAYS, naming W. Daniel Hillis, Nathan P.        Myhrvold, Clarence T. Tegreene, Lowell L. Wood, Jr., and        Victoria Y. H. Wood as inventors, filed Mar. 11, 2005, Ser. No.        11/078,206.    -   3. United States patent application entitled SELF ASSEMBLING        DISPLAY WITH SUBSTRATE, naming Daniel Hillis, Nathan P.        Myhrvold, Lowell L. Wood, Jr., Victoria Y. H. Wood, and        Clarence T. Tegreene as inventors, filed Apr. 4, 2005, Ser. No.        11/099,409.    -   4. United States patent application entitled METHOD OF        ASSEMBLING DISPLAYS ON SUBSTRATES, naming Daniel Hillis,        Nathan P. Myhrvold, Lowell L. Wood, Jr., Victoria Y. H. Wood,        and Clarence T. Tegreene as inventors, filed Apr. 4, 2005, Ser.        No. 11/099,682.

TECHNICAL FIELD

The present application relates, in general, to the field of displays,and particularly to methods of manufacture thereof.

BACKGROUND

Displays used in television screens, computer monitors, electronic signsor displays, and the like may be formed from arrays of large numbers oflight emitting elements that may be controlled to display time-varyingpatterns of light. Color displays typically include light emittingelements that emit light of several colors.

SUMMARY

Embodiments of methods and systems for constructing and configuringdisplays including superimposed display elements are disclosed herein.Features of various embodiments will be apparent from the followingdetailed description and associated drawings.

BRIEF DESCRIPTION OF THE FIGURES

Features of the invention are set forth in the appended claims. Theexemplary embodiments may best be understood by making reference to thefollowing description taken in conjunction with the accompanyingdrawings. In the figures, like referenced numerals identify likeelements.

FIG. 1 illustrates superposition of two display subunits to form asuperimposed display;

FIG. 2 illustrates superposition of two display subunits withcomplementary activation patterns;

FIG. 3 depicts optical superposition of display subunits formed on thesame substrate;

FIG. 4 depicts optical superposition of interleaved display subunitsformed on the same substrate;

FIG. 5 depicts physical superposition of display subunits formed on atransparent substrate;

FIG. 6 illustrates superposition of display subunits including severaldifferent colors of display elements;

FIG. 7 depicts superimposed linear arrays of display elements;

FIG. 8 illustrates superimposed two-dimensional arrays of displayelements;

FIG. 9 illustrates superimposed display subunits having non-uniformdistributions of display elements;

FIG. 10 depicts superimposed display subunits having partiallyoverlapping distributions of display elements;

FIG. 11 is a flow diagram of a method for configuring a superimposeddisplay;

FIG. 12 is a schematic diagram of electrical and optical components forconfiguring display elements;

FIG. 13 is a flow diagram of a method of configuring a superimposeddisplay;

FIG. 14 is a schematic diagram of a system including a superimposeddisplay;

FIG. 15 is a schematic diagram of a system including a superimposeddisplay;

FIG. 16 is a flow diagram of a method of configuring a superimposeddisplay;

FIG. 17 illustrates application of a superimposed display in a computersystem;

FIG. 18 illustrates application of a superimposed display in atelevision

FIG. 19 illustrates application of a superimposed display in a sign;

FIG. 20 illustrates application of a superimposed display on a wearableitem; and

FIG. 21 illustrates application of a superimposed display on adecorative item.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. The detaileddescription and the drawings illustrate specific exemplary embodimentsby which the invention may be practiced. These embodiments are describedin sufficient detail to enable those skilled in the art to practice theinvention. It is understood that other embodiments may be utilized, andother changes may be made, without departing from the spirit or scope ofthe present invention. The following detailed description is thereforenot to be taken in a limiting sense, and the scope of the presentinvention is defined by the appended claims.

Throughout the specification and claims, the following terms take themeanings explicitly associated herein unless the context dictatesotherwise. The meaning of “a”, “an”, and “the” include pluralreferences. The meaning of “in” includes “in” and “on.” A reference tothe singular includes a reference to the plural unless otherwise statedor inconsistent with the disclosure herein.

According to one exemplary embodiment, a display is formed bysuperimposing two display subunits. Each display subunit may includemultiple display elements or pixels which emit or otherwise modulatelight to produce a visually detectable pattern. FIG. 1 illustrates inschematic form the superposition of a first display subunit 10 includingdisplay elements 12 _(rc) (where row r=1 . . . 3 and column c=1 . . . 3)with a second display subunit 20 including display elements 22 _(rc)(where row r=1 . . . 3, and column c=1 . . . 3) to form a superimposeddisplay 30. Superimposed display 30 includes superimposed displayelements 32 _(rc) (where row r=1 . . . 3, and column c=1 . . . 3). Eachsuperimposed display element 32 _(rc) is formed from the superpositionof a display element 12 _(rc) from the first display subunit 10 and adisplay element 22 _(rc) from second display subunit 20. For example,superimposed display element 32 ₂₃ is formed from the superposition ofdisplay elements 12 ₂₃ and 22 ₂₃. Superimposed display element 32 ₂₃produces light modulation equal to the combined light modulation of thetwo superimposed display elements 12 ₂₃ and 22 ₂₃, from first displaysubunit 10 and second display subunit 20, respectively.

In the example depicted in FIG. 1, in first display subunit 10, displayelements 12 ₁₁, 12 ₁₂, 12 ₂₁, 12 ₂₃, 12 ₃₁, and 12 ₃₃, are functionaland display elements 12 ₁₃, 12 ₂₂, and 12 ₃₂ are non-functional. Insecond display subunit 20, display elements 22 ₁₂, 22 ₁₃, 22 ₂₁, 22 ₂₂,22 ₂₃, 22 ₃₁, and 22 ₃₃ are functional and display elements 22 ₁₁, and22 ₃₂ are non-functional. In superimposed display 30, superimposeddisplay elements 32 ₁₂, 32 ₂₁, 32 ₂₃, 32 ₃₁, and 32 ₃₃, are formed fromthe superposition of two functional display elements. Assuming eachfunctioning display element delivers light with a fluence of about X,then superimposed display elements 32 ₁₂, 32 ₂₁, 32 ₂₃, 32 ₃₁, and 32₃₃, deliver light with a fluence of about 2X. Superimposed displayelement 32 ₃₂ is formed from superposition of non-functional displayelement 12 ₃₂ in first display subunit 10 and non-functional displayelement 22 ₃₂ in second display subunit 20. Assuming eachnon-functioning display element does not produce any light (or has afluence of 0), then superimposed display element 32 ₃₂ also provideszero fluence and is non-functional. Superimposed display element 32 ₁₁is formed from the superposition of a functional display element 12 ₁₁from first display subunit 10 and a non-functional display element 22 ₁₁from second display subunit 20. Similarly, superimposed display elements32 ₁₃ and 32 ₂₂ are formed from the superposition of non-functionaldisplay elements 12 ₁₃ and 12 ₂₂ from first display subunit 10 andfunctional display elements 22 ₁₃ and 22 ₂₂, respectively, from seconddisplay subunit 20. Superimposed display elements 32 ₁₃ and 32 ₂₂ mayoperate at a fluence of about 1X, approximately half-power relative tosuperimposed display elements that are formed from superposition of twofunctional display elements.

Display elements may be considered bad, faulty, or non-functional ifthey are partially or fully non-functional, functional but not connectedproperly, or not positioned properly. Display elements may also beconsidered non-functional for non-defective reasons, such as design oroperational considerations. For example, display elements may be outsideof a desired wavelength range, in a location where light emission orcontrol is not desired, in a location where drawing energy (e.g., from arow driver) is inappropriate, or other considerations in which anon-functional element may be imposed or desired.

FIG. 1 depicts a case in which some superimposed display elements are‘on’ or operating at full power, while some superimposed displayelements are completely non-functional. Some superimposed displayelements (i.e. 32 ₁₁, 32 ₁₃, and 32 ₂₂) are partially functional. Insome applications, partial functionality (e.g., operation at about halffluence) would be acceptable performance for a display element, while inother applications, the fluence provided by a partially functionaldisplay element would be insufficient. In general, a display element maybe deemed ‘bad’ if its performance falls outside a specified range,which may vary depending on the intended application of the display.

In some cases it may be desirable to detect bad or non-functionaldisplay elements and to configure superimposed display elements tocompensate for the non-functional display elements. FIG. 2 depicts ageneral scheme for compensating for non-functional display elements. InFIG. 2, a first display subunit 40 is provided in which display elements42 ₃₂ and 42 ₃₃ are non-functional. Second display subunit 50 may beprovided to supplement operation of the non-functional display elementsin first display subunit 40. In this example, second display subunit 50may configured with display elements 52 ₃₂ and 52 ₃₃ functional (oractive) and display elements 52 ₁₁, 52 ₁₂, 52 ₁₃, 52 ₂₁, 52 ₂₂, 52 ₂₃,and 52 ₃₁ non-functional (or inactive) so that superposition of firstdisplay subunit 40 and second display subunit 50 produces superimposeddisplay 60 in which all display elements 62 _(rc) are functional withthe substantially the same intensity or dynamic range.

Non-functional display elements in a display subunit may be detected byvarious methods, during and/or subsequent to the manufacture of asuperimposed display element array. For example, a CCD camera may beused to detect activation of display elements. Display elements may beactivated in a specified pattern, and differences between the detectedpattern and the specified pattern pixels may indicated non-functionaldisplay elements. Activation of display elements may occur sequentially,simultaneously, or in any other pattern that is convenient for theparticular display being tested. Different elements may bedifferentiated by time sequential activation and detection, colorspecific activation and detection, and so forth. Activation of displayelements may be determined by any signal that correlates with displayelement activation. For example, electrical correlates such as voltagedrop or current may be measured in order to determine activation ofdisplay elements. Detection of electrical correlates may be performedwith circuitry built into the display subunit or by separate testequipment. In another approach for detecting and compensating for baddisplay elements, display elements may be activated at a prescribedoutput intensity and color (e.g., white at a given temperature andintensity). Deviations between the prescribed output and the measuredoutput may be determined, and drive levels for display elementsoptimized to compensate for element variations. Compensation may beprovided for variation in element performance, not limited to defects.

FIG. 3 illustrates an embodiment in which two display subunits 70 and 80are formed on a single substrate 90. In this exemplary embodiment, firstdisplay subunit 70, made up of display elements 72, 74, and 76, andsecond display subunit 80 made up of display elements 82, 84, and 86,are formed in the same plane, on face 91 of substrate 90. In relatedembodiments, first and second display subunits may be formed indifferent layers, levels, or surfaces of substrates. While in someembodiments layers, levels, or surfaces containing display subunits maybe planar or substantially planar, subunits may be formed in non-planarlayers, levels, or surfaces in other embodiments. Optical system 100receives optical signals (i.e. light) from first display subunit 70 andsecond display subunit 80 and combines them optically to formsuperimposed display 92, which includes superimposed display elements102, 104, and 106. Optical system 100 takes optical signal 73 fromdisplay element 72 and combines it with optical signal 83 from displayelement 82 to form optical signal 103. Optical system 100 and opticalsystems used in related embodiments may include one or more lenses,lenslets, reflectors, diffractive elements, combiners, polarizationselective elements, or waveguides. Structures such as an X-cube colorcombiner (e.g., as described by Brozzone et al, SID Symposium Digest ofTechnical Papers, May 2003, Vol. 34, Issue 1, pp. 126-129), may be usedin certain embodiments to optically superimpose display elements. Thelocation at which optical signal 103 is emitted from optical system 100functions as display element 102 of superimposed display 92. Similarly,optical system 100 takes optical signal 75 from display element 74 andcombines it with optical signal 85 from display element 84 to formoptical signal 105, and takes optical signal 77 from display element 76and combines it with optical signal 87 from display element 86 to formoptical signal 107. Optical signal 105 and 107 are emitted bysuperimposed display elements 104 and 106, respectively. Substrate 90may also include control lines 110, 112, and 114 for driving activationof display elements 72, 74, and 76, respectively, in first displaysubunit 70, and control lines 118, 120, and 122 for driving activationof display elements 82, 84, and 86, respectively, in second displaysubunit 80.

FIG. 4 illustrates an alternative embodiment in which two displaysubunits 132 and 134 are formed on substrate 130 in interleaved form:first display subunit 132 is made up of display elements 136, 138, and140, which alternate with display elements 142, 144, and 146 of seconddisplay subunit 134. Optical system 150 receives optical signals 152,154, and 156 from display elements 136, 138, and 140 of first displaysubunit 132, and optical signals 160, 162, and 164 from display elements142, 144, and 146 of second display subunit 134, and combines themoptically to form superimposed display 182, which is made up ofsuperimposed display elements 176, 178, and 180, which emit opticalsignals 170, 172, and 174, respectively. Optical system 150 may includeany of the various types of optical components, as discussed inconnection with FIG. 3. Substrate 130 may include control lines 184,186, and 188 for driving activation of display elements 136, 138, and140 in first display subunit 132 and control lines 190, 192, and 194 fordriving activation of display elements 142, 144, and 146 in seconddisplay subunit 134.

FIG. 5 depicts a further embodiment of a superimposed display in whichdisplay elements are formed in two planes of a substantially transparentsubstrate 200. First display subunit 201, made up of display elements202 _(rc), (row r=1 . . . 3, column c=1 . . . 4) is formed in a firstplane, on surface 204 of substrate 200. Second display subunit 205, madeup of display elements 206 _(rc), (row r=1 . . . 3, column c=1 . . . 4)is formed in a second plane, at second surface 208 of substrate 200.First display subunit 201 is physically superimposed on second displaysubunit 205. Substrate 200 may be substantially transparent to permitlight from first display subunit 201 and second display subunit 205 tobe visible from at least one direction, e.g., at first surface 204 ofsubstrate 200. In this context, substrate 200 may be consideredsubstantially transparent if it is substantially transparent towavelengths or wavebands emitted by display elements 202 _(rc), and 206_(rc), and not necessarily to other wavelengths or wavebands. In thisexample, display elements are superimposed physically and need not besuperimposed optically, though in some embodiments it may beadvantageous to use an optical system in combination with physicallysuperimposed display elements or display subunits. Various materials maybe used to form a transparent substrate as depicted in FIG. 5,including, but not limited to glass, various plastics (e.g. glass,polycarbonate, selected semiconductor materials, plastics, or otherpolymers) etc. Transparent light emitting or modulating elements mayalso be used, e.g. certain types of organic light emitting diodes suchas are commercially available from a number of sources.

In some embodiments, a display may include a first plurality of lightmodulating elements and a second plurality of light modulating elements,with each light modulating element of the second plurality superimposedwith a corresponding light modulating element of the first plurality toproduce a superimposed display element. Overlap of the first pluralityof light modulating elements and the second plurality of lightmodulating elements may form a plurality of superimposed displayelements that together form a superimposed display.

The display may also include electronic circuitry configured to controloperation of light modulating elements of the first plurality of lightmodulating elements to supplement operation of light modulating elementsin the second plurality of light modulating elements to produce adesired light modulation pattern in the superimposed display. In someembodiments, the electronic circuitry may be configured to control lightmodulating elements of the first plurality and light modulating elementsof the second plurality so that the desired light modulation pattern hasa higher spatial frequency content than light modulation patternsproduced by either of the first plurality and the second plurality. Inother embodiments, the electronic circuitry may be configured to controllight modulating elements of the first plurality and light modulatingelements of the second plurality so that the desired light modulationpattern is a time-varying light modulation pattern with a highertemporal frequency content than light modulation patterns produced byeither of the first plurality and the second plurality. In variousembodiments, the electronic circuitry may be configured to control lightmodulating elements of the first plurality and light modulating elementsof the second plurality so that the desired light modulation pattern hasa higher information content than light modulation patterns produced byeither of the first plurality and the second plurality. For example, theinformation represented in one or more parameters of the desired lightmodulation pattern may be represented by modulation of the amplitude,polarization, direction or spatial orientation of light emission, colorcontent, duration, or overall energy of light.

First and second display subunits used to form a superimposed displaymay be in the same substrate, as depicted in FIGS. 3-5. In someembodiments, first and second display subunits may be non-overlapping,but superimposed optically. They may be in the same layer, levels, orsurface of the substrate, or in different layers, levels, or surfaces ofthe substrate. Layers, levels, or surfaces containing superimposeddisplay subunits may be planar, as illustrate in FIGS. 3-5, ornon-planar. Moreover, layers, levels, or surfaces containingsuperimposed display subunits may be parallel in some embodiments, butin other embodiments may be non-parallel. First and second display unitsmay be interleaved. In some embodiments, e.g, as depicted in FIG. 5,first and second display subunits may be at least partially physicallyoverlapping. Display elements may not need to be perfectly physicallysuperimposed. If display elements are partially superimposed, ornon-superimposed but interleaved and sufficiently close to each other,they may be combined by the viewer's eye.

In some embodiments, display subunits may include two or more differenttypes of display elements. In the exemplary embodiment depicted in FIG.6, two display subunits 260 and 270 are provided, each of which includesthree different types of display elements. In this example, displayelements which emit light in red, green, and blue wavelength bands areincluded, as indicated by r, g, and b, respectively. Display elements indisplay subunit 260 are superimposed with display elements in displaysubunit 270 by optical system 290, which may include various componentsas described previously, such as one or more lenses, lenslets,reflectors, diffractive elements, combiners, polarization selectiveelements, or waveguides. For example, red display elements 262 and 268in display subunit 260 may be superimposed with red display elements 272and 278, respectively, in display subunit 270. Similarly, green displayelement 264 in display subunit 260 may be superimposed with greendisplay element 274 in display subunit 270, blue display element 266 indisplay subunit 260 may be superimposed with blue display element 276 indisplay subunit 270, and so forth. Thus, each display element may besuperimposed with a display element of a like type, which in thisexample is a display element that emits light in a like wavelength band.Superposition of display elements that emit light in the same wavelengthband (e.g., red display elements 262 and 272 in display subunits 260 and270, respectively) produces a superimposed display element that emitslight in the same wavelength band as the display elements from which itis formed (e.g. superimposed display element 284 in superimposed display290 emits red light).

As illustrated in FIG. 6, a display may include a first display subunitincluding a first plurality of light emitting elements and a seconddisplay subunit including a second plurality of light emitting elements.Each light emitting element in the first plurality and the secondplurality may be designed to emit light in a characteristic wavelengthband. The display may also include an optical system configured tooptically superimpose each light emitting element of the first pluralitywith a corresponding light emitting element of the second plurality,with superimposed light emitting elements designed to emit light in alike wavelength bands. In some embodiments, the display may also includeelectronic circuitry configured to control one or more light emittingelements in the second display subunit to compensate for one or more badlight emitting elements in the first display subunit. The electroniccircuitry may be configured to detect one or more bad light emittingelements in the first display subunit, and in response to adjust one ormore corresponding light emitting elements in the second display subunitto compensate for the one or more bad light emitting elements in thefirst display subunit.

Display subunits may include two or more subsets of light modulatingelements, with each subset designed to modulate light in a respectivewavelength band, and each respective wavelength band different from therespective wavelength band of at least one other subset of lightmodulating elements. If a display subunit includes two or more subsetsof light modulating elements, each subset of light modulating elementsmay be distinguishable from another of the two or more subsets by atleast one light emission parameter, including wavelength band envelope,spectral width, power, emission pattern, polarization, direction orspatial orientation of light emission, response speed, or linearity.Light modulating elements of the two or more subsets may be arranged ina repeating pattern according to the light modulation wavelength band ofthe light modulating elements. The first and second display subunits maybe controlled to simultaneously produce substantially identical firstand second light patterns within the superimposed display area. Lightemitting elements of the first display subunit may be opticallysuperimposed with light emitting elements of the same type in the seconddisplay subunit.

A display subunit may include at least two subsets of light emittingelements, with each subset including light emitting elements designed toemit light in one of at least two different characteristic wavelengthbands. For example, display subunits may include a first subset of lightmodulating elements designed to emit light in a red wavelength band, asecond subset of light modulating elements designed to emit light in agreen wavelength band, and a third subset of light modulating elementsdesigned to emit light in a blue wavelength band. In some embodiments,the first display subunit may be in a first substrate and the seconddisplay subunit may be in a second substrate. The first and secondsubstrates may be non-overlapping, or they may be at least partiallyoverlapping. In related embodiments, each of the first and seconddisplay subunits includes light emitting elements of at least two types,each type designed to emit light that differs from light emitted bydisplay elements of other types by one or more parameters includingwavelength band envelope, spectral width, power, emission pattern,polarization, direction or spatial orientation of light emission,response speed, or linearity, and wherein light emitting elements of thefirst display subunit are optically superimposed with light emittingelements of the same type in the second display subunit. Displaysubunits may have various configurations of display elements. Forexample, as depicted in FIG. 7, each of the first display subunit 300and second display subunit 304 may include a linear array of lightemitting elements 300 a-h and 306 a-h, respectively. In otherembodiments, as illustrated in FIG. 8, first display subunit 310 andsecond display subunit 312 may include two-dimensional arrays of lightemitting elements, 314 _(rc) and 316 _(rc), respectively (where r=1-4and c=1-3). Two types of light emitting elements may be arranged in likerepeating patterns in first and second display subunits. In someembodiments, the repeating patterns may be spatially periodic.

A display may include a first display subunit comprising a firstplurality of light modulating elements and a second display subunitcomprising a second plurality of light modulating elements. Each lightmodulating element of the first and second pluralities of lightmodulating elements may be designed to modulate light in a respectivecharacteristic pattern. The display may include an optical systemconfigured to optically superimpose each light modulating element of thefirst plurality with a corresponding light modulating element of thesecond plurality designed to modulate light in a like characteristicpattern. The display also may include electronic circuitry configured tocontrol operation of light modulating elements in the first displaysubunit to compensate for defective light modulating elements in thesecond display subunit.

As illustrated by the various disclosed embodiments, displays may beformed from the superposition of two or more display subunits includinga plurality of display elements on a substrate. Specific types ofdisplay elements may be positioned on a substrate at selected locations,to form a display having a desired arrangement of display elements. Insome embodiments, display elements may be formed integrally with thesubstrate, while in others, display elements may be formed separatelyfrom the substrate and subsequently positioned on the substrate. In someembodiments, display subunits may be formed separately and subsequentlycombined, while in other embodiments, display subunits may be distinctfunctional entities within the display but may be manufactured as asingle structure. Substrates on which display subunits are formed mayinclude, but are not limited to silicon based materials, semiconductormaterials, polymers, ceramics, metals, and composite materials.Substrates may include electrical lines for carrying power and controlsignals, formed by various methods as known to those of skill in therelevant arts. In some embodiments, substrates may include various typesof electronic circuitry, which may be used to control or configuredisplay subunits and superimposed displays.

Display elements in a display subunit may be arranged in a patternhaving short-range order or long-range order. Patterns having eithershort-range order or long-range order may incorporate repeatingpatterns. In an embodiment particularly suited for the design of threecolor displays, as commonly used in television or computer screens,three distinct types of display elements may be used. A repeatingpattern unit may include at least one red display element, at least onegreen display element, and at least one blue display element, asdepicted, for example, in FIG. 6.

Some embodiments may include display elements arranged in regular,rectilinear N×N or M×N arrays. However, display subunits may include notonly regular, rectilinear arrays, but also arrays formed from variousother configurations of display elements, including arrangements ofdisplay elements that are non-uniform with respect to variousparameters, including, but not limited to spacing, orientation, size,and type of display elements. Display subunits may include two or moredistinct regions, configured so that within each region the displayelement array is regular and uniform, but between regions and across thedisplay subunit as a whole, there is a non-uniform, irregulardistribution of display elements. For example, as depicted in FIG. 9,first display subunit 320 includes a central region 322 that contains anarray of display elements 324 at a first spacing and a border region 326that contains display elements 328 at a second spacing. In this example,display elements 324 in central region 322 are more closely spaced thandisplay elements 328 in border region 326. Second display subunit 330similarly includes central region 332 made up of display elements 334and border region 336 made up of display elements 338. If displaysubunit 320 is superimposed on display subunit 330, there is aone-to-one correspondence between display elements 324 and 334, anddisplay elements 328 and 338, and the resulting superimposed displaywill have the same display elements configuration as each of displaysubunits 320 and 330. In some embodiments, display subunits may includearrangements of display elements that do not include uniform regions butare non-uniform as a whole. Non-uniform distributions may includegradients with respect to display element size, color, etc., forexample, running from one side of a display subunit to another, or fromthe center of a display element array to the edges. Non-uniform displaysubunits may be non-uniform but have a statistical distribution ofdisplay elements over some or all of the subunit. In certainembodiments, spatial distribution of display elements over a subunit maybe random or quasi-random.

In many cases, there will be a one-to-one correspondence between displayelements in display subunits to be superimposed, and the subunits andthe superimposed display formed from the subunits will all have the samenumber and arrangement of display elements. However, in certainembodiments, a portion, but not all of the display elements may besuperimposed, and the display element configuration will not beidentical between the display subunits and the resulting superimposeddisplay. For example, as illustrated in FIG. 10, first display subunit350 may include display elements 352 arranged in a first pattern, andsecond display subunit 360 may include display elements 362 arranged ina second pattern. Superposition of first display subunit 350 and seconddisplay subunit 360 produces superimposed display 370, which includes aplurality of superimposed display elements 372, and also independentdisplay elements 352 from first display subunit 350, and independentdisplay elements 362 from second display subunit 360, which are notsuperimposed with any other display elements.

Display elements may include various types of light modulating elements.Light modulating elements may include elements which modulate lightperceived by a viewer of the display. In some embodiments, lightmodulating elements may be light emitting elements. Light emittingelements may be organic or inorganic wavelength converters, phosphors,fluors, laser diodes, light emitting diodes, organic light emittingdiodes, polymer light emitting diodes, quantum dots, electroluminescentdevices, chemiluminescent devices, polymers, or nonlinear opticalmaterials. Each type of light emitting element may be capable ofemitting light in a respective wavelength band. Light emitting elementsmay be capable of emitting light in a wavelength band corresponding toone or more colors, responsive to a control signal. A display elementsuitable for assembly into multicolor displays having a plurality ofelements may include a light emitting element capable of emitting lightin respective range corresponding to one or more of the colors of thedisplay. Light emitting elements may be capable of emitting light in awavelength band corresponding to one or more colors, responsive to acontrol signal. Light emitting elements may emit light in response to anelectrical control signal (e.g., current or voltage), and/or anelectromagnetic control signal (e.g., an electron beam or incidentlight). In some embodiments, light modulating elements may modify ormodulate light incident on the display to produce a particular visuallydetectable effect on the display by, for example, absorbing, reflecting,diffracting, scattering or otherwise modifying light impinging on thedisplay. Thus, in such embodiments, display elements may have acharacteristic light absorption spectrum, reflection spectrum, etc.,instead of or in addition to a light emission spectrum. Light modulatingelements may function to vary one or more light parameters, includingbut not limited to amplitude, polarization, direction or spatialorientation of light emission, color content, duration, or overallenergy of light. Light modulating elements may include various devicesor structures, including nematic crystals, polarizers, photoabsorptivematerials, MEMS structures, or optical polymers, or other types ofelements that can vary the amplitude, polarization, color content,duration, overall energy or other aspects of the light.

In various embodiments, superimposed display subunits are configured tocompensate for ‘bad’, non-functioning, or malfunctioning displayelements. The use of superimposed display subunits offers thepossibility of providing enhanced display element function relative towhat can be obtained with a single display element. By superimposingdisplay elements, it is possible to produce superimposed displayelements having a broader dynamic range, broader spectral composition,or other features. By superimposing display elements having differentspectral wavebands, it is possible to produce superimposed displayelements with a spectral waveband that might not be produced (or mightnot be produced in a convenient or practical manner) by a single displayelement. If superimposed display elements are of different types(varying in waveband, optical polarization, direction or spatialorientation of light emission, or any of various other parameters), itmay be possible to provide various enhanced display properties. Enhanceddisplay properties may include light emission or modulation patternswith greater information content, with information being reflected inmodulations of any of various light parameters, including but notlimited to those listed above and elsewhere herein. By controllingspatial and temporal patterns of activation of display elements in thedisplay subunits appropriately, light modulation patterns may beproduced which have greater complexity than may be obtained with anydisplay element individually. For example, groupings of display elementsin the superimposed display may be produced by offsetting displaysubunits relative to each other so that display elements are notperfectly superimposed, but are adjacent each other in the superimposeddisplay. Simple or low frequency patterns of activation of displayelements in a single subunit can be superimposed with other simple/lowfrequency activation patterns in other subunits to produce more complexand higher frequency activation patterns in the superimposed display.Thus, displays formed by superposition of two, three, or more displaysubunits may produce a much wider variety of light modulation patternsthan are available with a single display subunit or single layerdisplay.

Display elements may be distinguished from each other by variouscharacteristics, of which the following are only exemplary: intensity ofemitted light, power consumption, size, shape, wavelength band envelope,spectral width, spectral content, power, intensity, brightness,irradiance, emission pattern, direction or spatial orientation ofemission, polarization, response speed, and linearity. Moreover, displayelements may have a characteristic spectral response that is not basedupon light emission, but rather upon some form of light modulation,including, but not limited to, light reflection, refraction, absorption,or scattering. Display elements may include various types oflight-emitting or -modulating elements. Each type of light-emittingelement may be capable of emitting light in a respective wavelengthband. Light-emitting elements may be, for example, inorganic wavelengthconverters, organic wavelength converters, phosphors, fluors, laserdiodes, light-emitting diodes, organic light-emitting diodes, polymerlight-emitting diodes, quantum dots, polymers, polymer,electroluminescent devices, chemiluminescent devices, or nonlinearoptical materials. Display elements that are formed separately andsubsequently assembled to a substrate may include a polymeric carrier ora silicon-based carrier. Light-emitting elements may be capable ofemitting light in a wavelength band corresponding to one or more colors,responsive to a control signal. Light-modulating elements may includestructures including nematic crystals and polarizers, such as thosefound in LCDs, photoabsorptive materials, MEMS structures, opticalpolymers, or other types of elements that can vary the amplitude,polarization, color content, pulse-duration or pulse-format, overallenergy or other aspects of the light. Although specific types of lightmodulating elements may be referenced in connection with certainexemplary embodiments described herein, unless it is stated that aparticular type of light modulating element is required for use in aparticular embodiment, it should be assumed that other types of lightmodulating elements may be used in the embodiment as well.

Display elements may be formed separately and subsequently assembledinto an array to form a display subunit. Such display elements aredescribed, for example, in United States patent application entitledELEMENTS FOR SELF-ASSEMBLING DISPLAYS, filed Mar. 11, 2005, Ser. No.11/078,207, and in United States patent application entitled SELFASSEMBLING DISPLAY WITH SUBSTRATE, filed Apr. 4, 2005, Ser. No.11/099,409, both of which are incorporated herein by reference in theirentirety. Alternatively, display elements may formed integrally with asubstrate to form a display subunit. Display elements formed by variousmethods may include various components in addition to a light modulatingor light emitting element. A display element may include one or moreinputs for receiving power and/or control signals. For example, thedisplay element may include at least one contact for forming anelectrical or optical connection with a substrate or another displayelement to receive power or control signals. In some embodiments, thedisplay element may include a radio transmitter, receiver or transceiverfor sending or for receiving an RF control or data signal. The displayelement may include a power signal input such as a receiver coil orantenna for receiving electromagnetic power. In some embodiments,display elements may include various other structures that convertenergy or power received from external sources to light, including, forexample, photovoltaic, fluorescent, and chemiluminescent devices. Insome embodiments, the display element may include a power source, whichmay be a battery or other power-generating, -collecting, -transducing or-accumulating device or structure, such as a photovoltaic cell, aninductive coil, an antenna, or an energy-scavenging device.

Control signals for controlling generation or modulation of light by adisplay element may be transmitted to display elements via data-linkssuch as acoustic, optical, magnetic or electrical links. Displayelements may include a transceiver that allows data and control signalsto be sent between display elements and external control circuitry,without electrical connections between display elements. Displayelements may be responsive to control signals in the form of electricalor electromagnetic energy (e.g., UV light or an electron beam) targetedon the display element. Display elements may emit light in response toan electrical control signal (e.g., current or voltage), anelectromagnetic control signal (e.g., an electron beam or incidentlight), or other control signal. A display element may emit light inresponse to a control signal. In some embodiments, a display element mayturn off in response to the control signal, while in still otherembodiments, the pattern of light emission or modulation produced by adisplay element may be modulated by a control signal; e.g., theamplitude or pulse frequency of emitted light may be modified inresponse to a control signal. The response of a display element to acontrol signal may be modified by electronic circuitry or components inor associated with the display element, which may store one or moreconfiguration settings for the display element. For example, a controlsignal may direct a display element to ‘turn on’ or ‘turn off’, whilethe amplitude of light emission may be controlled by a gain valuesetting stored in the display element. Various parameters lightmodulation by the display element may be determined at least in part byone or more configuration settings stored in the display element, whichmay be stored in the form of data values stored in a memory location, inthe setting of electronic circuitry, or in other forms as known by thoseof skill in the relevant arts. A configuration setting in a displayelement may regulate various parameters of light emission, including butnot limited to pulse repetition pattern, wavelength band envelope,spectral width, intensity, emission pattern, polarization, direction orspatial orientation of light emission, response speed, or linearity.

In some embodiments, each display element may include a uniqueidentifier. Each display element may be capable of storing identifyinginformation. The unique identifier may be a number or code stored invarious formats detectable or readable by external devices and/or byother components within the display. For example, the unique identifiermay be an RFID or other type of electromagnetically responsive element.The unique identifier may be a pattern of bits stored in any of varioustypes of data storage elements in or on the display element, forexample, in electronic, optical, or magnetic form. In some embodiments,the identifying information may be updatable, for example, by circuitryon the display element, by a control signal sent from the substrate, orby a control signal sent from a location remote from the substrate. Theidentifying information may include address information specifying thelocation of the display element on the substrate. Various identificationstructures other than RFID structures may also be appropriate.Electromagnetically responsive elements that are responsive toelectromagnetic radiation of various other frequencies, for example,microwave and sub-RF frequencies, may be used as identificationstructures or tags. Electromagnetically responsive elements for use asidentification structure are not limited those that are responsive toany particular frequency range. In other embodiments, each displayelement may include an optically responsive structure that respondsselectively to its respective identification information.

By superimposing two display subunits, it is possible to reduce thenumber of non-functioning display elements in the superimposed displayrelative to the display subunits. If both display subunits are drivenwith the same activation or control signal, the image generated by thesuperimposed display may have fewer defects than the image produced byeither display subunit by itself. For example, in FIG. 1, bysuperimposing two display subunits, each of which contains threenon-functioning display elements, it is possible to produce asuperimposed display that has only one completely non-functioningdisplay element. Of the functioning display elements, several operate at1X fluence, and several operate at 2X fluence, which may be satisfactoryfor many applications.

An alternative method of modifying display performance is exemplified bythe scheme depicted in FIG. 2, in which display elements 52 _(rc) in asecond display subunit 50 are activated in a pattern specificallyselected to compensate for defects in a first display subunit 40. In thesuperimposed display 60, superimposed display elements 62 _(rc) allproduce light at the same fluence level, because each superimposeddisplay element is formed from one active or functional display elementsuperimposed with one inactive or non-functional display element.

In order to configure subunits of a superimposed display to operate asdepicted in FIG. 2, a process may be performed as shown in FIG. 11. FIG.11 depicts an exemplary method of configuring a display includingsuperimposed first and second display subunits, which includes the stepsof producing a test illumination pattern on the first display subunit atstep 402, detecting defects in the test illumination pattern at step404, and configuring the second display subunit to produce anillumination pattern sufficient to compensate at least in part fordefects in the test illumination pattern, at step 406. Configuring thesecond display subunit may include configuring an electronic circuitcontrolling activation of the second display subunit, which may entailconfiguring one or more of hardware, software, or firmware controllingactivation of the second display subunit.

With regard to steps 402 and 404 in FIG. 11, various test illuminationpatterns may be used, and various approaches may be used for detectingthe generated illumination. In one alternative, all display elements maybe illuminated simultaneously. In other alternatives, one or a fewdisplay elements may be illuminated in a known sequence. Illumination ofa display element may be detected with an optical sensor, by detectingan electrical correlate of display element illumination, or by detectingany other parameter that provides an indication of whether or not adisplay element is functional.

In some embodiments, display units may be tested and configured prior toassembly. In other embodiments, display subunits may be assembled toform a superimposed display, and subsequently tested and configured. Oneexemplary method of producing a display includes superimposing first andsecond display subunits having substantially identical arrangements oflight modulating elements to form a superimposed display area, whereineach light modulating element of the first display subunit is designedto modulate light in a respective characteristic pattern, and whereineach light modulating element of the first display subunit within thesuperimposed display area is superimposed with a light modulatingelement of the second display subunit designed to modulate light of alike characteristic pattern. The method may include controlling thefirst display subunit to produce a first light pattern and controllingthe second display subunit to produce a second light pattern that whensuperimposed with the first light pattern produces a desired lightpattern. The method may also include detecting the first light patternand adjusting the second light pattern responsive to the detected firstlight pattern to compensate for differences between the first lightpattern and the desired light pattern. Detecting a first light patternmay include detecting the light pattern optically. Alternatively,detecting a first light pattern may include detecting an electricalcorrelate of the light pattern. The method may include opticallysuperimposing or physically superimposing the first display subunit andthe second display subunit. In some embodiments, first and seconddisplay subunits may be controlled to produce a desired light modulationpattern having a higher spatial frequency content than light modulationpatterns produced by either of the first display subunit and the seconddisplay subunit. In other embodiments, first and second display subunitsmay be controlled to produce a time-variant desired light modulationpattern having a higher temporal frequency content than light modulationpatterns produced by either of the first display subunit and the seconddisplay subunit. In general such methods may be considered to produce alight modulation in the superimposed display area that has increasedinformation content relative to the light modulation pattern produced byeither of the display subunits independents. In further exemplaryembodiments, the first and second display subunits may be controlled toproduce a desired light modulation pattern having a higher informationcontent than light modulation patterns produced by either of the firstdisplay subunit and the second display subunit. For example, theinformation represented in one or more parameters of the desired lightmodulation pattern may be represented by modulation of the amplitude,polarization, direction or spatial orientation of light emission, colorcontent, duration, or overall energy of light

FIG. 12 provides an example of electrical and optical components thatmay be used to configure superimposed first and second display elements500 and 502, which may be members of arrays of display elements insuperimposed display subunits. For example, display element 500 may be adisplay element in a first display subunit, and display element 502 maybe a display element in a second display subunit. A common driver signal501 is delivered to display element 500 on input line 503 and to displayelement 502 on input line 505. Driver signal 501 corresponds to adesired output for the superimposed display element formed from displayelement 500 and display element 502. In response to driver signal 501,display element 500 may produce a light output 504. Display element 500may also produce a logic signal A (e.g., a voltage signal) on line 506.Logic signal A indicates whether or not display element 500 isfunctioning properly. Logic signal A may be derived from an electroniccorrelate of light generation by display element 500 through the use ofappropriate electronic circuitry, as known by a person of skill in theelectronic arts. For example, if display element 500 is an LED, if theLED has broken down and is not functioning properly, the flow of currentthrough the LED will be altered relative to the current flow obtainedduring normal operation (either there will be no conductance through theLED, or the LED will function as a conductor in the reverse direction,both conditions that can be detected by appropriately configuredcircuitry). In this example, Logic signal A has a value of 1 whendisplay element 500 is functioning properly, and a value of 0 when it isnot functioning properly. Similarly, display element 502 may produce alight output 508 in response to driver signal 501, and a logic signal Bon line 510, which has a value of 1 when display element 502 isfunctioning properly and a value of 0 when it is not functioningproperly. Logic signal A and logic signal B are delivered to the inputsof NAND gate 512. As illustrated in logic table 530 in FIG. 12, when thevalues of logic signals A and B are both 1, the output Q of NAND gate512 is 0. For all other combinations of values of logic signals A and B,the output Q of NAND gate 512 is 1. Output Q is delivered to filter 516via line 514. Filter 516 is an electronically configurable opticalfilter that may be in an optically conductive or open state when Q is 1.Devices of this type are may include LCD elements, electroabsorptivedevices, or other types of controllable elements. When Q is 0, filter516 assumes an optically non-conductive or closed state, indicated byreference number 516′. When filter 516 is in a conductive state, light504 from display element 500 is directed to filter 516 by reflector 520,passes through filter 516, and combined with light 508 from displayelement 502 at combiner 524 to form combined (superimposed) light 526.Thus, light 504 and 508, from display elements 500 and 502,respectively, will be superimposed if either of the display elements isnot functioning properly, thus compensating for the defective displayelement. However, if both display element 500 and display element 502are functioning properly, filter 516 assumes a non-conductive state,indicated by reference number 516′ in FIG. 12, which does not permit thepassage of light, and light 504 from display element 500 is not combinedwith light 508 from display element 502.

FIG. 13 illustrates an additional method of configuring a display formedfrom first and second display units. At step 602, a test illuminationpattern is generated on a first display subunit. At step 604, the testillumination pattern is detected. At step 606, bad display elements inthe first display subunit are determined. At step 608, a second displaysubunit is configured to compensate for bad element(s) in the firstdisplay subunit.

FIG. 14 illustrates a system 700 in which electronic circuitry is usedto configure display elements. Controller 702 generates a drive signal704 that specifies a particular light modulation pattern 722. Drivesignal 704 is received by configuration circuitry 706. Configurationcircuitry 706 includes electronic circuitry for configuring displayelements, which may include electronic circuitry for turning on or off(activating or deactivating) selected display elements, or for adjustingthe gain of selected display elements. Activation, deactivation, or gainmay be set or adjusted. Configuration circuitry 706 may be configured ina relatively permanent fashion, e.g., during the manufacture of thedevice, or it may be modifiable during the lifetime of the device. Ifconfiguration circuitry 706 is modifiable, system performance may bemodified in response to changes in display element performance duringuse of the device, or in situations where a change in system performanceis desired for some other reason. Configuration circuitry 706 modulatesselected components of drive signal 704 to generate a first subunitdrive signal 708 and second subunit drive signal 710. First subunitdrive signal 708 drives first display subunit 712 to produce first lightmodulation pattern 716, and second subunit drive signal 710 drivessecond display subunit 714 to produce second light modulation pattern718. First light modulation pattern 716 and second light modulationpattern 718 are superimposed by optical system 720 to produce lightmodulation 722.

In some embodiments, only one display subunit may be configured tomodify performance of the superimposed display element. In otherembodiments, the performance of two (or more) display subunits elementsmay be configured, by setting or adjusting activation, deactivation, orgain. On/off setting, gain adjustment, switching, etc. as used toconfigured display elements may be performed in hardware, software, orfirmware, by methods known to those of skill in the relevant arts. Itwill be appreciated that configuration can be done at the level of thedisplay subunit or display, or at the level of the software and/orhardware that provides driver signals to the display. Configurationperformed at the level of the display subunit may include storing aconfiguration setting on or in association with individual displayelements, by setting the value or state of a data storage element orelectronic circuit component of a display element to reflect a desireddisplay/emission mode. Such display/emission mode may be selected frommultiple pre-set intensities, directions, polarizations,pulse-repetition patterns, etc. in which the display element may be ableto operate. For example, a display element may be set to an ‘on’configuration if a display element with which it is superimposed isknown to be non-functional. As another example, the gain of a displayelement may be set so that when used in combination with another displayelement, a desired total gain may be obtained.

FIG. 15 is a schematic diagram of a system 800 including a superimposeddisplay 802. System 800 may be any of various types of systems that mayutilize superimposed displays as described herein, including computers,televisions, and telephones, among others. Superimposed display 802 isformed from a first display subunit 804 and second display subunit 806superimposed by optical system 808. System 800 includes microprocessor810, input device 820, memory 822, and power supply 824. Input device820 may be, for example, a keyboard, key pad, microphone, mouse, trackball, switch, radio receiver, or other input devices as known to thoseof skill in the art. System 800 may include one or more output devices,including superimposed display 802. System 800 may also includeadditional output devices, such as speakers, recording devices, etc.Based upon input from input device 820 and the current status of system800, a control signal 826 is generated by microprocessor 810 andtransmitted to configuration module 828. Control signal 826 may containinstructions for a desired image to be displayed on superimposed display802. Configuration module 828 may receive control signal 826 andmodulate certain components of control signal 826 (by modifying gain,etc.) to generate first subunit control signal 830 and second subunitcontrol signal 832, for controlling display subunits 804 and 806respectively. In response to first unit control signal 820 and secondsubunit control signal 832, display subunits 804 and 806 generate firstlight modulation pattern 840 and second light modulation pattern 842,respectively, which are superimposed by optical system 808 to produceoutput light modulation pattern 844, the output of superimposed display802. Configuration module 828 may be either hardware, software, or acombination thereof. If software, configuration module 828 may reside inmemory 822 of system 800. If hardware or firmware, configuration module828 may take the form of a component of system 800, or may be acomponent of superimposed display 802.

Control signals for controlling generation or modulation of light by adisplay element may be transmitted to display elements via optical orelectrical links. Control signals may include electrical signalstransmitted via electronic circuitry, electromagnetic signalstransmitted to display elements via a transmitter and received by areceiver (or transceiver), optical signals delivered via opticalcircuitry or electromagnetic signal. Display elements may be responsiveto control signals in the form of electromagnetic energy (e.g., UV lightor an electron beam) targeted on the display element. Display elementsmay emit light in response to an electrical control signal (e.g.,current or voltage), an electromagnetic control signal (e.g., anelectron beam or incident light), or other control signal. A controlsignal may cause emission of light by a light emitting element directly(e.g., in the case of an electron beam, UV beam, or other energystriking a phosphor to cause emission of light) or a control signal maybe processed by electronic or optical circuitry on the light emittingelement to control light emission indirectly, in which case the controlsignal may initiate, stop, or otherwise modulate the emission of lightby light emitting elements. In some embodiments, a display element mayturn off in response to the control signal, while in still otherembodiments, the pattern of light emission or modulation produced by adisplay element may be modulated by a control signal; e.g., theamplitude or pulse frequency of emitted light may be modified inresponse to a control signal.

A variety of approaches to selectively activating individual elements,or groups of elements may be implemented. In a straightforward N×N orM×N array of elements, conventional row and column addressing, such asthat found in many matrix array structures, such as LCDs, may beappropriate. The control electronics and tradeoffs for such addressingand selective activation are known to one of skill in the art. Thedisplay may include electronic circuitry configured for carryingelectrical control signals to selected receptor locations on thesubstrate to control display elements at the selected receptorlocations. The display may also include optical circuitry configured forcarrying optical control signals to one or more selected receptorlocations on the substrate to control display elements at the selectedreceptor locations. In some embodiments, the display may also comprisean electromagnetic radiation source, and each display element of theplurality of display elements may be selectively activatable bydirecting the radiation source toward the display element to activatethe display element. The electromagnetic radiation source may include anelectron gun or an ultraviolet radiation source. Display elements may beselectively activatable by electromagnetic energy directed onto theselected display elements at selected locations on the display. Controlsignals may include electromagnetic energy, e.g., ultraviolet radiationor an electron beam, and electrical signal, an optical signal, orvarious other control signals, as known to those of skill in therelevant art.

FIG. 16 illustrates a method of improving performance of a display,through the use of superimposed display subunits. Display performancemay be improved by superimposing first and second display subunitshaving substantially identical arrangements of light emitting elementsto form a superimposed display area, at step 902. Step 904 includesdetecting the presence of at least one malfunctioning light emittingelement in the first display subunit within the superimposed displayarea. If the malfunctioning light emitting element in the first displaysubunit is superimposed on a functioning light emitting element in thesecond display subunit, the operation of the functioning light emittingelement is controlled to at least partially compensate for themalfunctioning light emitting element at step 906. In many embodiments,it will be the case that each light emitting element of the firstdisplay subunit is designed to emit light of a characteristic wavelengthband and is superimposed with a light emitting element of the seconddisplay subunit designed to emit light of the same wavelength band. Amalfunctioning light emitting element may be a light emitting elementthat is functioning in a manner deviating from an expected operation.The method of may include operating light emitting elements in the firstand second display subunits at respective intermediate power levelsbetween 25% and 75% of an expected emission level if corresponding lightemitting elements in both the first display subunit and the seconddisplay subunit are functioning. Controlling the operation of thefunctioning light emitting element to at least partially compensate forthe malfunctioning light emitting element may include operating thefunctioning light emitting element at a level greater than 75% of theexpected emission level. In a system such as that depicted in FIG. 15,operating a light emitting element at a selected intermediate powerlevel may be accomplished, for example, by setting gain values inconfiguration module 828 appropriately for each display element.

Embodiments as described herein may be incorporated into varioussystems, including, for example, computer systems, television, amongothers. Basic components of such systems may include a processor, aninput device, and a display. A superimposed display, as used in variousembodiments, may be a display which includes a first display subunitcomprising a first plurality of light emitting elements, of which eachlight emitting element may be designed to emit light in a characteristicwavelength band, a second display subunit comprising a second pluralityof light emitting elements, an optical system configured to opticallysuperimpose each light emitting element of the first plurality with acorresponding light emitting element of the second plurality designed toemit light in the same wavelength band, and electronic circuitryconfigured to modulate activation of selected light emitting elements inthe first plurality to compensate for defects in corresponding lightemitting elements in the second plurality.

If the system is a computer system, for example, the superimposeddisplay may be a computer monitor and the input device may be a computerkeyboard, as illustrated in FIG. 17.

FIG. 18 depicts application of a superimposed display 1010 in atelevision screen 1012. It is increasingly the case that there is littledistinction between television screens and computers monitors, astelevisions include more interactive capabilities, and televisionscreens include capabilities for displaying images in multiple windows,displaying menu option, and so forth.

FIG. 19 illustrates the use of a superimposed display on a sign 1020.Sign 1020 includes a static display portion 1022 that may be configuredto display a static image 1024 (in this case, the text “Coffee Shop &Billiards”), and a dynamic display portion 1026 that may be configuredto display a message or image 1028 that may be changed at intervals. Ifdesired, the dynamic display portion may display a continuously changingmessage or image (e.g., scrolling text or animated image). Staticdisplay portion 1022 and dynamic display portion 1026 may differ withregard to type and distribution of display elements, or with regard tothe control signals used to control the display elements. Signs (andrelated displays, such as labels, advertisements, billboard, etc., whichmay also incorporate embodiments of the present invention) may beentirely static, entirely dynamic or mixed-modal, depending on theirintended use. Sign 1020 may include battery 1030 and control circuitry1032 mounted in or on sign 1020 for driving operation of static displayportion 1022 and dynamic display portion 1024.

Superimposed displays may also be used on items of apparel, or otherdecorative or functional items formed of flexible fabric or material. Asan example, FIG. 20 illustrates the use of a superimposed display on abaseball cap 1050. Baseball cap 1050 includes panel 1052 containingsuperimposed display 1054, which may be formed on a flexible substrate.Text, images, or patterns, which may be either static or dynamic, may bedisplayed on superimposed display 1054. In the example shown in FIG. 20,superimposed display 1054 displays text 1056, reading “GO TEAM!”Superimposed display 1054 may be powered by various methods. As shown inFIG. 20, a small battery 1058 may be mounted on cap 1050 in aninconspicuous location (e.g., in the interior of cap 1050) and connectedto superimposed display 1054 via lead 1064. Alternative power suppliesmay be used instead, e.g., a solar cell. Controller 1060, which may bean ASIC- or a microprocessor-based device, may be mounted on cap 1050and connected via one or more data-lines 1062 to superimposed display1054 to drive operation of superimposed display 1054.

FIG. 21 illustrates the use of a superimposed display on a decorativeitem having a non-planar substrate: in this example, a vase 1200 bearinga panel 1202 displaying the message “Get Well Soon!”. The message “GetWell Soon!” may alternate with one or more other messages or images, mayscroll across the panel, may flash, or may produce various other visualeffects. Such variations of displays may be applied to any otherembodiments in which a dynamic display element array is used, includingbut not limited to the examples presented herein. Vase 1200 mayincorporate a battery or other power supply and control circuitry, asdiscussed in connection with the baseball cap embodiment depicted inFIG. 20.

Superimposed displays may be used in virtually any setting in which itis desired to graphically display static or dynamic text, images, orpatterns on a surface. As discussed previously, dynamic displays may bevaried at intervals (for example, dynamic display portion 1026 in FIG.19 may be changed from “Closed—Come back Soon” to “Open—Come on In”), ormay be varied continuously to display scrolling or flashing text,animated graphic, or various other dynamic displays as may be devised bythose of skill in the relevant arts. Display elements may be of a widerange of sizes, and superimposed displays may be of a wide range ofsizes and resolutions, depending on intended application andconstruction method and materials. Text, images, and patterns formedthrough the use of such displays may be informative, decorative, orfunctional. Such displays may be used in or on a wide variety ofdecorative and/or functional items, to convey information or to changethe appearance of an item in a functional manner (e.g., camouflage orvisual signature-reduction on a vehicle or item of clothing), or topresent a desired decorative appearance on various items (objects, itemsof apparel, etc., signs, labels, artwork.)

With regard to the hardware and/or software used in the control ofdisplays according to the present embodiments, and particularly to thecontrol of light generation by display elements within such displays,those having skill in the art will recognize that the state of the arthas progressed to the point where there is little distinction leftbetween hardware and software implementations of aspects of suchsystems; the use of hardware or software is generally (but not always,in that in certain contexts the choice between hardware and software canbecome significant) a design choice representing cost vs. efficiency orimplementation convenience tradeoffs. Those having skill in the art willappreciate that there are various vehicles by which processes and/orsystems described herein can be effected (e.g., hardware, software,and/or firmware), and that the preferred vehicle will vary with thecontext in which the processes are deployed. For example, if animplementer determines that speed and accuracy are paramount, theimplementer may opt for a hardware and/or firmware vehicle;alternatively, if flexibility is paramount, the implementer may opt fora solely software implementation; or, yet again alternatively, theimplementer may opt for some combination of hardware, software, and/orfirmware. Hence, there are several possible vehicles by which theprocesses described herein may be effected, none of which is inherentlysuperior to the other in that any vehicle to be utilized is a choicedependent upon the context in which the vehicle will be deployed and thespecific concerns (e.g., speed, flexibility, or predictability) of theimplementer, any of which may vary.

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beimplicitly understood by those with skill in the art that each functionand/or operation within such block diagrams, flowcharts, or examples canbe implemented, individually and/or collectively, by a wide range ofhardware, software, firmware, or virtually any combination thereof. Inone embodiment, several portions of the subject matter described hereinmay be implemented via Application Specific Integrated Circuits (ASICs),Field Programmable Gate Arrays (FPGAs), digital signal processors(DSPs), or other integrated formats. However, those skilled in the artwill recognize that some aspects of the embodiments disclosed herein, inwhole or in part, can be equivalently implemented in standard integratedcircuits, as one or more computer programs running on one or morecomputers (e.g., as one or more programs running on one or more computersystems), as one or more programs running on one or more processors(e.g., as one or more programs running on one or more microprocessors),as firmware, or as virtually any combination thereof, and that designingthe circuitry and/or writing the code for the software and/or firmwarewould be well within the capabilities of one of skill in the art inlight of this disclosure. In addition, those skilled in the art willappreciate that certain mechanisms of the subject matter describedherein are capable of being distributed as a program product in avariety of forms, and that an illustrative embodiment of the subjectmatter described herein applies equally regardless of the particulartype of signal bearing media used to actually carry out thedistribution. Examples of a signal bearing media include, but are notlimited to, the following: recordable type media such as floppy disks,hard disk drives, CD ROMs, digital tape, and computer memory; andtransmission type media such as digital and analog communication linksusing TDM or IP based communication links (e.g., links carryingpacketized data).

In a general sense, those skilled in the art will recognize that thevarious aspects described herein which can be implemented, individuallyand/or collectively, by a wide range of hardware, software, firmware, orany combination thereof can be viewed as being composed of various typesof “electrical circuitry.” Consequently, as used herein “electricalcircuitry” includes, but is not limited to, electrical circuitry havingat least one discrete electrical circuit, electrical circuitry having atleast one integrated circuit, electrical circuitry having at least oneapplication specific integrated circuit, electrical circuitry forming ageneral purpose computing device configured by a computer program (e.g.,a general purpose computer configured by a computer program which atleast partially carries out processes and/or devices described herein,or a microprocessor configured by a computer program which at leastpartially carries out processes and/or devices described herein),electrical circuitry forming a memory device (e.g., forms of randomaccess memory), and/or electrical circuitry forming a communicationsdevice (e.g., a modem, communications switch, or optical-electricalequipment).

Those skilled in the art will recognize that it is common within the artto describe devices for displaying or otherwise presenting informationin the fashion set forth herein, and thereafter use standard engineeringpractices to integrate such described devices and/or processes intodisplays or other light emitting or modulating devices as exemplifiedherein. That is, at least a portion of the devices and/or processesdescribed herein can be integrated into a display or other lightemitting or modulating device containing system via a reasonable amountof experimentation.

Those having skill in the art will recognize that such systems generallyinclude one or more of a memory such as volatile and non-volatilememory, processors such as microprocessors and digital signalprocessors, computational-supporting or associated entities such asoperating systems, user interfaces, drivers, sensors, actuators,applications programs, one or more interaction devices, such as dataports, control systems including feedback loops and control implementingactuators (e.g., devices for sensing position and/or velocity and/oracceleration or time-rate-of-change thereof, control motors for movingand/or adjusting components and/or quantities). A typical display systemmay be implemented utilizing any suitable available components, such asthose typically found in appropriate computing/communication systemsand/or light emitting systems, combined with standard engineeringpractices.

The foregoing-described aspects depict different components containedwithin, or connected with, different other components. It is to beunderstood that such depicted architectures are merely exemplary, andthat in fact many other architectures can be implemented which achievethe same functionality. In a conceptual sense, any arrangement ofcomponents to achieve the same functionality is effectively “associated”such that the desired functionality is achieved. Hence, any twocomponents herein combined to achieve a particular functionality can beseen as “associated with” each other such that the desired functionalityis achieved, irrespective of architectures or intermediate components.Likewise, any two components so associated can also be viewed as being“operably connected”, or “operably coupled”, to each other to achievethe desired functionality.

While particular aspects of the present subject matter described hereinhave been shown and described, it will be obvious to those skilled inthe art that, based upon the teachings herein, changes and modificationsmay be made without departing from this subject matter described hereinand its broader aspects and, therefore, the appended claims are toencompass within their scope all such changes and modifications as arewithin the true spirit and scope of this subject matter describedherein. Furthermore, it is to be understood that the invention isdefined by the appended claims. It will be understood by those withinthe art that, in general, terms used herein, and especially in theappended claims (e.g., bodies of the appended claims) are generallyintended as “open” terms (e.g., the term “including” should beinterpreted as “including but not limited to,” the term “having” shouldbe interpreted as “having at least,” the term “includes” should beinterpreted as “includes but is not limited to,” etc.). It will befurther understood by those within the art that if a specific number ofan introduced claim recitation is intended, such an intent will beexplicitly recited in the claim, and in the absence of such recitationno such intent is present. For example, as an aid to understanding, thefollowing appended claims may contain usage of the introductory phrases“at least one” and “one or more” to introduce claim recitations.However, the use of such phrases should NOT be construed to imply thatthe introduction of a claim recitation by the indefinite articles “a” or“an” limits any particular claim containing such introduced claimrecitation to inventions containing only one such recitation, even whenthe same claim includes the introductory phrases “one or more” or “atleast one” and indefinite articles such as “a” or “an” (e.g., “a” and/or“an” should typically be interpreted to mean “at least one” and/or “oneor more”); the same holds true for the use of definite articles used tointroduce claim recitations. In addition, even if a specific number ofan introduced claim recitation is explicitly recited, those skilled inthe art will recognize that such recitation should typically beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, typicallymeans at least two recitations, or two or more recitations).Furthermore, in those instances where a convention analogous to “atleast one of A, B, and C, etc.” is used, in general such a constructionis intended in the sense of one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, and C”would include but not be limited to systems that have A alone, B alone,C alone, A and B together, A and C together, B and C together, and/or A,B, and C together). In those instances where a convention analogous to“at least one of A, B, or C, etc.” is used, in general such aconstruction is intended in the sense of one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, or C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together).

Although the methods, devices, systems and approaches herein have beendescribed with reference to certain preferred embodiments, otherembodiments are possible. As illustrated by the foregoing examples,various choices of light modulating elements, subunit configuration, andcontrol system may be within the scope of the invention. As has beendiscussed, the choice of system configuration may depend on the intendedapplication of the system, the environment in which the system is used,cost, personal preference or other factors. Display design, manufacture,and control processes may be modified to take into account choices ofdisplay element components and configuration, and such modifications, asknown to those of skill in the arts of display design and construction,may fall within the scope of the invention. Therefore, the full spiritor scope of the invention is defined by the appended claims and is notto be limited to the specific embodiments described herein.

1. A display comprising: a) a first display subunit comprising a firstplurality of light emitting elements, each light emitting element ofsaid first plurality designed to emit light in a characteristicwavelength band; b) a second display subunit comprising a secondplurality of light emitting elements, each light emitting element ofsaid second plurality designed to emit light in a characteristicwavelength band; and c) an optical system configured to opticallysuperimpose each light emitting element of said first plurality with acorresponding light emitting element of said second plurality designedto emit light in a like wavelength band.
 2. The display of claim 1,further comprising electronic circuitry configured to control one ormore light emitting elements in said second display subunit tocompensate for one or more bad light emitting elements in said firstdisplay subunit.
 3. The display of claim 1, further comprisingelectronic circuitry configured to detect one or more bad light emittingelements in said first display subunit, and in response to adjust one ormore corresponding light emitting elements in said second displaysubunit to compensate for said one or more bad light emitting elementsin said first display subunit.
 4. The display of claim 1, wherein eachof said first and second display subunits comprises light emittingelements of at least two types, each type designed to emit light thatdiffers from light emitted by display elements of other types by one ormore parameters including wavelength band envelope, spectral width,power, emission pattern, polarization, direction or spatial orientationof light emission, response speed, or linearity, and wherein lightemitting elements of said first display subunit are opticallysuperimposed with light emitting elements of the same type in saidsecond display subunit.
 5. The display of claim 4, wherein said at leasttwo types of light emitting elements are arranged in like repeatingpatterns in said first and second display subunits.
 6. The display ofclaim 1, wherein said first and second display subunits are in the samesubstrate.
 7. The display of claim 6, wherein said first and seconddisplay subunits are in the same layer, level, or surface of saidsubstrate.
 8. The display of claim 7, wherein said first and seconddisplay subunits are arranged in one of an interleaved arrangement, anat least partially overlapping arrangement, or a non-overlappingarrangement.
 9. The display of claim 6, wherein said first and seconddisplay subunits are in two different layers, levels, or surfaces ofsaid substrate.
 10. The display of claim 9, wherein said first andsecond display subunits are arranged in one of an interleavedarrangement, an at least partially overlapping arrangement, or anon-overlapping arrangement.
 11. The display of claim 1, wherein saidfirst display subunit is in a first substrate and said second displaysubunit is in a second substrate.
 12. The display of claim 11, whereinsaid first and second substrates are arranged in one of anon-overlapping arrangement and an at least partially overlappingarrangement.
 13. The display of claim 1, wherein said optical systemincludes one or more lenses, lenslets, reflectors, diffractive elements,combiners, polarization selective elements, or waveguides.
 14. Thedisplay of claim 1, wherein said first display subunit comprises atleast two subsets of light emitting elements, wherein each subsetincludes light emitting elements designed to emit light in one of atleast two different characteristic wavelength bands.
 15. The display ofclaim 1, wherein said first display subunit comprises a first subset oflight emitting elements designed to emit light in a red wavelength band,a second subset of light emitting elements designed to emit light in agreen wavelength band, and a third subset of light emitting elementsdesigned to emit light in a blue wavelength band.
 16. The display ofclaim 1, wherein each of said first and second display subunitscomprises at least one of a linear array of light emitting elements or atwo-dimensional array of light emitting elements.
 17. The display ofclaim 1, wherein said light emitting elements comprise at least one oforganic wavelength converters, inorganic wavelength converters,phosphors, fluors, laser diodes, light emitting diodes, organic lightemitting diodes, polymer light emitting diodes, quantum dots, polymers,electroluminescent devices, chemiluminescent devices, or nonlinearoptical materials.
 18. A method of producing a display, comprising: a)superimposing first and second display subunits having substantiallyidentical arrangements of light modulating elements to form asuperimposed display area, wherein each light modulating element of saidfirst display subunit is designed to modulate light in a respectivecharacteristic pattern, and wherein each light modulating element ofsaid first display subunit within said superimposed display area issuperimposed with a light modulating element of said second displaysubunit designed to modulate light in a like characteristic pattern; b)controlling said first display subunit to produce a first light pattern;and c) controlling said second display subunit to produce a second lightpattern that when superimposed with said first light pattern produces adesired light pattern in said superimposed display area.
 19. A systemcomprising: a) a processor; b) an input device; and c) a displayincluding: i) a first display subunit comprising a first plurality oflight emitting elements, each light emitting element of said firstplurality designed to emit light in a characteristic wavelength band;ii) a second display subunit comprising a second plurality of lightemitting elements; iii) an optical system configured to opticallysuperimpose each light emitting element of said first plurality with acorresponding light emitting element of said second plurality designedto emit light in the same wavelength band; and iv) electronic circuitryconfigured to modulate activation of selected light emitting elements insaid first plurality to compensate for defects in corresponding lightemitting elements in said second plurality.
 20. The system of claim 19,wherein said display is a computer monitor or a television screen.
 21. Amethod of producing a display, comprising: a) superimposing first andsecond display subunits having substantially identical arrangements oflight modulating elements to form a superimposed display area, whereineach light modulating element of said first display subunit is designedto modulate light in a respective characteristic pattern, and whereineach light modulating element of said first display subunit within saidsuperimposed display area is superimposed with a light modulatingelement of said second display subunit designed to modulate light in alike characteristic pattern; b) controlling said first display subunitto produce a first light pattern; c) controlling said second displaysubunit to produce a second light pattern that when superimposed withsaid first light pattern produces a desired light pattern in saidsuperimposed display area; d) detecting the presence of at least onemalfunctioning light modulating element in said first display subunitwithin said superimposed display area, said malfunctioning lightmodulating element functioning in a manner deviating from an expectedoperation; and e) if said malfunctioning light modulating element insaid first display subunit is superimposed on a functioning lightmodulating element in said second display subunit, controlling theoperation of said functioning light modulating element to at leastpartially compensate for said malfunctioning light modulating element.22. The method of claim 21, including operating light modulatingelements in said first and second display subunits at respectiveintermediate power levels between 25% and 75% of an expected modulationlevel if corresponding light modulating elements in both said firstdisplay subunit and said second display subunit are functioning, andwherein controlling the operation of said functioning light modulatingelement to at least partially compensate for said malfunctioning lightmodulating element includes operating said functioning light modulatingelement at a level greater than 75% of the expected modulation level.23. The method of claim 21, comprising detecting said first lightpattern and adjusting said second light pattern responsive to saiddetected first light pattern to compensate for differences between saidfirst light pattern and said desired light pattern.
 24. The method ofclaim 23, wherein detecting said first light pattern includes at leastone of detecting said light pattern optically or detecting an electricalcorrelate of said light pattern.
 25. The method of claim 21, whereinsaid first and second display subunits are controlled to produce adesired light modulation pattern having a higher spatial frequencycontent than light modulation patterns produced by either of said firstdisplay subunit and said second display subunit.
 26. The method of claim21, wherein said first and second display subunits are controlled toproduce a time-variant desired light modulation pattern having a highertemporal frequency content than light modulation patterns produced byeither of said first display subunit and said second display subunit.27. The method of claim 21, wherein said first and second displaysubunits are controlled to produce a desired light modulation patternhaving a higher information content than light modulation patternsproduced by either of said first display subunit and said second displaysubunit, said information represented in one or more parameters of saiddesired light modulation pattern including amplitude, polarization,direction or spatial orientation of light emission, color content,duration, or overall energy of light.
 28. The method of claim 21,including at least one of optically superimposing said first displaysubunit and said second display subunit or physically superimposing saidfirst display subunit and said second display subunit.
 29. The method ofclaim 21, wherein said first display subunit comprises two or moresubsets of light modulating elements, wherein each subset of lightmodulating elements is distinguishable from another of said two or moresubsets by at least one light emission parameter, including wavelengthband envelope, spectral width, power, emission pattern, polarization,direction or spatial orientation of light emission, response speed, orlinearity.